Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Quem era a modelo do centrofold quando Krysten Ritter jogou 20 perguntas?
 ###Tabelas: CREATE TABLE wildcats_in_the_nba (wildcats_in_the_nba_id AUTO_INCREMENT PRIMARY KEY, Position VARCHAR, Name VARCHAR, Height VARCHAR, Weight (lbs.) INT, Hometown VARCHAR, Draft Year INT, Pick VARCHAR, All-Stars VARCHAR, NBA Championships VARCHAR, NBA Team VARCHAR) CREATE TABLE bus_fleet (bus_fleet_id AUTO_INCREMENT PRIMARY KEY, Manufacturer VARCHAR, Model VARCHAR, Year Built INT, Vehicle Length VARCHAR, Fuel Type VARCHAR, # in fleet INT) CREATE TABLE 2012 (2012_id AUTO_INCREMENT PRIMARY KEY, Date VARCHAR, Cover model VARCHAR, Centerfold model VARCHAR, Interview subject VARCHAR, 20 Questions VARCHAR, Pictorials VARCHAR) CREATE TABLE ground_history (ground_history_id AUTO_INCREMENT PRIMARY KEY, Name of ground VARCHAR, Location VARCHAR, Year VARCHAR, FC matches INT, LA matches INT, T20 matches INT, Total INT) CREATE TABLE norwegian_clubs'_performance_in_europe (norwegian_clubs'_performance_in_europe_id AUTO_INCREMENT PRIMARY KEY, Team VARCHAR, Contest and round VARCHAR, Opponent VARCHAR, 1st leg score* VARCHAR, 2nd leg score** VARCHAR, Aggregate score VARCHAR)  
SELECT Centerfold model FROM 2012 WHERE 20 Questions = Krysten Ritter